2723 Abdominal Aortic Aneurysm: An Uncommon Cause of Gastric Outlet Obstruction

Abstract

INTRODUCTION: Gastric outlet obstruction is a highly uncommon presentation for abdominal aortic aneurysm. CASE DESCRIPTION/METHODS: A 65 year old male with past medical history of AAA, HCV treated with Harvoni, GERD with gastritis, and HTN presented with intractable nausea and non-bloody, bilious vomiting for 6 hours associated with sudden onset generalized abdominal pain. Patient reports that he had been having regular bowel movements and passing flatus in the days leading up to presentation. GERD had been previously well-controlled with a PPI. Physical exam revealed a 5 cm pulsating mass in the epigastrium. CTA demonstrated gross distension of both the stomach and the proximal duodenum. The abdominal aortic aneurysm measured 5.2 cm by 4.2 cm and extended over 10 cm in length; an increasingly large false lumen was also noted. There was no other obstructing lesion appreciated on CT, either intra- or extra-luminal. The enlarging aortic aneurysm impinged upon and caused the obstruction of the distal duodenum. DISCUSSION: An expanding abdominal aortic aneurysm can compress the duodenum against the mesenteric artery or abdominal wall, causing gastric outlet obstruction; this obstruction leads to patients presenting with nausea and vomiting. Aortoduodenal syndrome was first described in 1905 by Osler. There are a few dozen case reports of aortoduodenal syndrome in the literature. Any patients presenting with protracted vomiting and pulsatile abdominal mass should raise suspicion for aortoduodenal syndrome. Abdominal tenderness and distension are not common findings in this syndrome. CT is required to rule out an alternative cause of duodenal obstruction; diagnosis may be confirmed with upper GI series with contrast or upper endoscopy. Patient should be initially optimized with gastric decompression, fluid resuscitation, and electrolyte correction before preceding to definitive treatment. Previously, gastric bypass was the general treatment prior to the introduction of surgical aortic repair. Aortic aneurysm repair is the mainstay of therapy with endovascular repair becoming increasingly common.